Boulder County – Sunset Pond Project

Fourmile Creek, Boulder County, CO

Fourmile Watershed Coalition and Four Mile Fire Protection District

CDBG-DR & EWP Sunset Pond Project

The Fourmile Watershed Coalition (FWC) awarded Frontier a contract to a construct a resilient stream channel design along approximately 450 LF of Fourmile Creek in Boulder County, CO. The project was designed by the NRCS as part of the NRCS’s Emergency Watershed Protection (EWP) program. Funding was also provided from the Colorado Water Conservation Board (CWCB) and a Community Development Block Grant – Disaster Recovery (CDBG-DR) Watershed Resilience Pilot Program. The 2013 flood deposited substantial debris and sediment above the diversion to the Sunset Pond. This resulted in Fourmile Creek cutting a new incised, unstable channel that was producing several head cuts. The Four Mile Fire District utilizes Sunset Pond as a source for water for the upper four miles of Fourmile Canyon Drive. This project removed sediment and debris from the existing channel and realigned the channel back to the original point of diversion. A new diversion box was fabricated and installed in conjunction with a cross vane to reliably deliver water to Sunset Pond at set flows. The project included construction of five boulder cross vanes and reconstructed a boulder step pool system. Toe rock was installed to stabilize the new channel along with 150 willow cuttings and 450 containerized plants. Seed, soil amendments, erosion control fabric and wood straw mulch were also used to revegetate the site. Due to site constraints and a desire to minimize the impact to private property, the entire project was constructed with a mini-excavator and skid steer. Including placement of some 3 ton boulders. Frontier self-performed all aspects of the project.